DUTCH ONION BOTTLE: BLACK GLASS
First off Black Glass is not the color of black glass. It is either dark olive green or dark amber mainly from the impurities in the glass. These free blown bottles can date from the 1600s to the early 1800s and are full of crudeness and caricter.
Below is a Dutch Onion from 1715 to 1725 give or take some years.
These bottles are called Dutch or Lowland bottles or the common name to call them are onion bottles because of the shape.
These bottle were blown by the Dutch, Belgians and Germans just to name a few. Most of these bottle have a pontil the size of a quarter.
Larger pontil onions bottles were mostly English blown.
Here are two tell tale signs of these bottles. Flat bottom very horseshoe shaped are earlier. More rounded bottoms which are usually squatier seem to be later.
Frank & Frank Jr. (Wicker) Bottle Collection.